Inerting method and apparatus for preventing and extinguishing fires in enclosed spaces

Abstract

An inerting method for reducing the risk of and for extinguishing fires in enclosed space as well as apparatus for carrying out the method are provided. To ensure an effective extinction of a fire while keeping the storage capacity for inert gas cylinders at a minimum, the method provides that the oxygen content in the enclosed space is reduced to a set base inerting level and, in the event of a fire, is quickly further reduced to a complete inerting level. For carrying out the method, the apparatus includes an oxygen measuring device in the enclosed space, with a first system for producing the oxygen-expulsion gas or for extracting oxygen from the enclosed space, with a second system for rapidly feeding an oxygen-expulsion gas into the space being monitored, and with a fire detection device for detecting a fire characteristic in the enclosed space. Also, a control unit is provided which sends a base inerting signal to the first system in accordance with the oxygen content in the enclosed space, and which sends a complete inerting signal to the second system in accordance with a detection signal from the fire detection device.

1 . An inerting method for reducing the risk of and for extinguishing fires in enclosed spaces, said method comprising the steps of 
 reducing a natural existing oxygen content in a wall-enclosed space to a selected base inerting level, and    in a case of a fire, rapidly further reducing the oxygen content to a selected complete inerting level.    
     
     
         2 . The method according to  claim 1 , including the additional steps of, 
 prior to the first reducing step, measuring the oxygen content in the enclosed space, and    controlling the reduction to the base inerting level in accordance with the measured value of the oxygen content in the enclosed space.    
     
     
         3 . The method according to  claim 1  or  2 , including the additional step of, prior to the further reducing step, in the event of a fire, detecting selected fire characteristics in said enclosed space and producing a complete inerting signal in response thereto to initiate the further reducing step.  
     
     
         4 . The method according to  claim 3 , wherein the detecting step includes 
 constantly extracting representative samples of the air in said enclosed space for preventing a fire, and    feeding the samples to a fire characteristics detector to produce said complete inerting signal.    
     
     
         5 . The method according to  claim 1  or  2 , wherein natural existing oxygen content in the enclosed space is reduced to the selected base inerting level by producing and/or introducing an oxygen-expulsion gas into the enclosed space.  
     
     
         6 . The method according to claims  1  or  2 , wherein the oxygen content in the enclosed space is reduced to the selected base inerting level by extracting oxygen from the enclosed space.  
     
     
         7 . The method according to claims  1  or  2 , wherein the further reduction step includes the introducing of an oxygen-expulsion gas into the enclosed space.  
     
     
         8 . The method according to  claim 7 , wherein said oxygen-expulsion gas is introduced from gas cylinders.  
     
     
         9 . The method according to  claim 5 , including the step of controlling the producing and/or introducing said oxygen-expulsion gas into the enclosed space in accordance with the measured oxygen content in the enclosed space.  
     
     
         10 . Inerting apparatus for carrying out the method of  claim 1  or  2 , said apparatus including a nitrogen generating machine.  
     
     
         11 . Inerting apparatus for carrying out the method according to  claim 2 , said apparatus comprising 
 an oxygen measuring device for measuring the oxygen content in said enclosed space for preventing a fire and producing a base inerting signal in response thereto;    a first system for producing the oxygen-expulsion gas or for extracting oxygen from the enclosed space to produce said base inerting level;    a second system for rapidly feeding an oxygen-expulsion gas into the enclosed space to produce the complete inerting level;    a fire detector for detecting a fire characteristic in the enclosed space and producing a complete inerting signal in response thereto, and    a control unit responsive to the base inerting signal and the complete inerting signal for sending a first control signal to the first system to maintain said base inerting level within the enclosed space, and sending a second control signal to the second system in response to said complete inerting signal to achieve said complete inerting level.    
     
     
         12 . The device according to  claim 11 , wherein the fire detector comprises an aspirative fire detection device having a housing.  
     
     
         13 . The device according to  claim 12 , wherein the oxygen measuring device is integrated into the housing of the fire detection device.